1. Technical Field
The present invention relates to a method and structure for forming a metalized blind via.
2. Related Art
Electroplating a metal (e.g., copper) on a sidewall of a blind via in a dielectric layer, wherein an exposed metal layer is at a bottom end of the blind via, may be included within an overall process that forms conductive circuitry in (and on) an electronic structure such as a chip carrier. The electroplating process may be preceded by electrolessly plating the metal on the sidewall, and the electroless plating may be facilitated by first forming a layer of a seeding material (e.g., palladium) on the sidewall prior to the electroless plating. The electroless plating layer, and the associated seeding layer underneath, form a thin continuous layer as part of a closed conductive circuit that may be required for subsequent electroplating, but unfortunately add time and expense to the overall process.
There is a need for a method that enables a blind via to be electroplated without prior electroless plating.
The present invention provides a method for forming an electronic structure, comprising:
forming a dielectric layer on a metallic layer, wherein the dielectric layer includes a dielectric material having carbon, and wherein the metallic layer includes a metallic material; and
laser drilling a depression in the dielectric layer such that a carbon film that includes the carbon is formed on a sidewall of the depression, wherein the carbon film is in conductive contact with the metallic layer, wherein the carbon film is sufficiently conductive to permit electroplating a continuous layer of metal directly on the carbon film, and wherein the laser drilling is with a laser radiation having a wavelength between about 180 nanometers and about 600 nanometers.
The present invention provides an electronic structure, comprising:
a metallic layer that includes a metallic material;
a dielectric layer on the metallic layer, wherein the dielectric layer includes a dielectric material having carbon; and
a depression in the dielectric layer; and
a carbon film on a sidewall of the depression, wherein the carbon film is in conductive contact with the metallic layer, and wherein the carbon film is sufficiently conductive to permit electroplating a continuous layer of metal directly on the carbon film.
The present invention enables a blind via to be electroplated without prior electroless plating.